Trills are encoded in **kern spines using either T or t markers
in note tokens:
The interval used in the trill is indicated by the case of the letter:
upper-case T indicates that the trill interval is a major second, while
a lower-case t indicates a minor second.
When the chromatic alteration of the auxiliary note of the trill is not in the key signature or the current state for the given diatonic pitch, then an accidental for the auxiliary note is given above the trill mark:
Notice in the above example that any accidental on an auxiliary trill
note will be canceled if a following primary note is on the same
diatonic pitch but with a different chromatic alteration. For example
the minor second trill on middle C (the first note in the above example)
is to a D-flat. Since the following note is a D-natural, a cancellation
accidental is typically added to the note to avoid performing it as a
D-flat. To hide the natural accidentals in the above example, add ny
to the notes to hide the natural signs:
The n character means that the note has a natural accidental, and the y
character means that the natural should not be shown.
Line extensions
Duplicating the trill character in the token will cause an extension line to be added to the trill.
To continue the line extension over several notes, use two trill characters to start the trill with a line extension, and then use three trill characters on each note which should be under the same trill line extension.
Notes under the trill line do not have to all be tied, as demonstrated by the first G in measure three of the above example. In addition, the following G-sharp is included under the trill extension line even though it is not the same pitch-class as the note that started the trill.
When trills are encoded in the second subspine, the trill marks and lines will be placed below the staff automatically: